The invention is directed generally to industrial doors, and more specifically to a release mechanism for allowing an industrial door to break away from its associated guide track upon an applied force above a certain magnitude.
A wide variety of doors are used in industrial settings. Such industrial doors include conventional sectional doors, comprising a series of panels hinged together to form the door. Typically, such a sectional door is movable between doorway-blocking positions and overhead-storing positions. For this purpose, a curved guide track is disposed on either side of the doorway, with one leg (adjacent to the doorway opening) extending vertically along the doorway, and the second leg (projecting back from the doorway opening) disposed above and behind the doorway. A curved track section joins the two legs. Sectional doors may also be vertically stored, that is they may have straight tracks and be movable in a continuous plane between doorway-blocking and doorway-opening positions. Typically, the panels comprising such a sectional door are formed of either metal or wood.
In other types of industrial doors, the door itself may be formed of fabric. One such type of fabric industrial door is a roll-up door, in which the door is a curtain of fabric rolled on a roller tube typically disposed above the doorway opening. To close the door, the curtain is drawn off of the roller, and the roller is reversed to roll the curtain up on the roller for the purpose of opening the door. Another type of fabric industrial door is a so-called xe2x80x9cconcertinaxe2x80x9d door. In a concertina door, the door typically also comprises a fabric curtain and a roller is disposed above the doorway opening. Straps are wound onto and off of the roller, and are connected typically to a leading edge of the curtain for the purpose of drawing the curtain up out of the way of the door opening, and allowing the curtain to fall and unfold to cover the door opening. The curtain itself does not wind on the tube, however, and rather is gathered in folds at the top of the door. A still further type of fabric industrial door is a sheet of fabric that is maintained in a flat orientation, and is moved between a doorway-blocking and a doorway-opening position. The doorway opening position may either be above the doorway or overhead, similar to an overhead-style sectional door. Further, while all of these doors have been described as moving vertically, they may also be modified such that their movement between door opening and door closing positions is in a horizontal or other direction, as opposed to a vertical direction. Roll-up doors comprising metal or chain sections are also known.
All of the industrial doors just described typically share a common feature of having a member extending across the doorway opening when the doorway is either in the closed or any of a variety of doorway-blocking positions. Such structure will be referred to herein as an xe2x80x9cextension member.xe2x80x9d In sectional doors, the extension members are the door panels themselves. Fabric doors typically include either a relatively rigid bottom bar extending across the leading edge of the door, and/or other relatively rigid bars extending across the width of the door at locations other than at the leading edge (these are often referred to as xe2x80x9cwind barsxe2x80x9d as they assist in adding stability to the door and preventing it from billowing under wind load conditions).
A common problem associated with such doors as a result of the presence of these extension members extending across the doorway is unintentional impact. In an industrial or warehouse setting, such impact may occur by virtue of a fork lift or other material handling equipment (or a load carried thereon) being driven into the door and the impact is thus directly or indirectly transmitted to the extension members. In situations where such doors are used in automated factories, conveyors or other devices may cause objects being conveyed to accidentally impact the doors. Given the fact that such impacts are bound to occur, certain types of industrial doors can be designed to withstand such impacts. For example, the panels comprising a sectional door, and the associated track and hardware can be reinforced to withstand such impacts. Of course, this adds significant expense to the door. Further, fabric-type industrial doors typically do not have this option as the door itself is formed of fabric which is more easily damaged than the metal or wood typically comprising sectional doors.
Accordingly, another solution to allowing industrial doors to withstand impact is to allow them to have a controlled breakaway under such an impact. That is, the door is designed for certain components to separate upon an unintentional impact, thus protecting the remainder of the door. One example of such a structure is shown in U.S. Pat. No. 4,676,293, assigned to the assignee of the present invention. In that patent, a sectional door is disclosed that includes a bottom panel having significant flexibility, thus allowing it to absorb impact. However, if the impact is above a predetermined magnitude, the door is designed to allow the roller associated with the bottom-most panel to disengage from the panel, thus allowing the panel to swing free relative to the rest of the door. This action protects the bottom panel from damage.
The various breakaway mechanisms disclosed in the prior art may adequately perform the desired function, but may be limited in use to certain environments or types of doors. In other circumstances, the disclosed breakaway mechanisms may not adequately function. Even when they do function properly, however, reassembly or repair of such doors following breakaway may be a cumbersome or time-consuming process. Spare parts may need to be maintained on hand, and trained technicians may need to be called to reassemble the door following breakaway. Complex breakaway mechanisms may also significantly increase the costs associated with a given door.
Another common problem associated with industrial door applications is unintentional impact on the tracks guiding the doors. Such track impacts occur from vehicles being driven into the tracks directly or vehicles hitting the tracks as they accidentally impact on doors or objects near the tracks. The tracks are typically mounted on the inside wall of the doorway and, thus, mostly impacted by vehicles traveling in one direction through the doorway. These impacts may damage the track and its alignment and prevent the door from smooth guided movement. As such, these unintentional impacts often necessitate the replacement of the tracks, which is time consuming and costly.
It would be advantageous to have a guard or shield for a track to protect it from unintentional impacts. Some shields which protect tracks from impact are commercially available, for example, the Warden(trademark) TR Sectional Door Guard available from Rite-Hite Aftermarket Corporation of Milwaukee, Wis. Such guards are mounted to an external wall and/or an adjacent floor to allow easy installation. It is desirable in some applications, however, to have a guard that can mount directly with the door track, to add further protection from impacts. Furthermore, it is desirable to provide guards that facilitate breakaway and that protect the track from damage during the impact.
Accordingly, it is the primary aim of the present invention to provide an improved releasing mechanism for industrial door as compared to those previously provided.
In accordance with that aim, it is an object of the invention to provide an industrial door release mechanism that provides simple construction and operation.
It is the further object of the invention to provide an industrial door release mechanism that allows for easy reassembly of the door following a breakaway condition.
A still further object is to provide an inexpensive and reliable release mechanism that may be used on a variety of industrial doors.
In accordance with other embodiments, there is provided a guiding mechanism for use with an industrial door. The industrial door includes an extension member extending across a doorway opening. The track is mounted to a guard bracket extending along the doorway. The guard bracket protects the track during a track impact condition. The guard bracket has a mounting segment upon which the track is mounted and a guard segment that protects the track during a track impact condition.
The guard bracket may be mounted to a wall defining the doorway, either directly or indirectly. In some embodiments the guard segment includes a overhang member that extends at least partially along a direction parallel to an inner face of the mounting segment offering further protection of the track.
In an embodiment, the track is movable relative to the wall upon application of a track impact force to the guard bracket. The relative movement in response to the track impact force further protects the track from damage during the track impact. In another embodiment, the track is movable relative to the wall upon application of a breakaway force to the extension member of the door, which might happen with the door in the blocking or partially blocking position. The relative movement here allows a roller or just the end of the extension member traveling within the track to escape from the track upon either a breakaway condition or a track impact condition. To achieve relative movement, the guard bracket is preferably mounted to the wall through a resilient member. Relative movement may also be achieved by mounting the track to the guard bracket through a resilient member. In both, the preferred resilient member is deformed or compressed to allow the track to move relative to the wall. Furthermore, the resilient member preferably returns to its original shape after the condition is removed.
The invention also encompasses a novel method for protecting a track during a track impact condition, where the track guides movement of an industrial door having an extension member and being moveable between blocking and unblocking positions relative to a doorway. The method comprises the step of mounting a guard bracket along the doorway, the guard bracket having a guard segment extending at least partially parallel to the doorway. A further step includes affixedly mounting a track to the guard bracket such that the guard segment protects the track form impact from a track impact force applied to the guard segment.
In some embodiments, the method further comprises the steps of mounting the guard bracket to a first resilient member and mounting the first resilient member to a wall defining the doorway, the first resilient member being mounted to the guard bracket such that the first resilient member deforms in response to the track impact force applied to the guard segment to allow the track to move relative to the wall.
In some embodiments, the method further comprises the step of disposing a second resilient member between the track and the guard bracket such that the second resilient member deforms in response to the track impact force applied to the guard segment to allow the roller to escape from the track.
The embodiments of the invention will be described herein in reference to the appended drawings, wherein: